ci: uninstall matplotlib

Author: ntamas

.github/workflows/build.yml

@@ -336,6 +336,9 @@ jobs:
           IGRAPH_USE_SANITIZERS: 1
         run: |
           pip install --prefer-binary '.[test]'
+          # Uninstall Matplotlib because Matplotlib-related tests cause false positives in the
+          # leak sanitizer checks
+          pip uninstall matplotlib
 
       # Only pytest, and nothing else should be run in this section due to the presence of LD_PRELOAD.
       # The ASan/UBSan library versions need to be updated when switching to a newer Ubuntu/GCC.